1. Technical Field
The present invention relates to an eyeglass lens design method, an eyeglass lens manufacturing method, an eyeglass lens, an eyeglass lens design system, an eyeglass lens design program and a recording medium.
2. Description of Related Art
A progressive power lens that includes a far-vision portion formed as a region for relatively long-distance vision, located at an upper position in the lens when it is worn as part of an eyeglass, a near-vision portion formed as a region for shorter-distance vision relative to the far-vision portion, located at a lower position in the lens, and a progressive portion located between the far-vision portion and the near-vision portion, which is formed as a region that connects the far-vision portion and the near-vision portion by continuously altering the surface refractive power, is utilized as a corrective eyeglass lens in order to compensate for deterioration in the accommodation ability due to presbyopia in the known art.
For purposes of optical performance improvement, a progressive power lens is now designed by evaluating the lens performance with beams of light equivalent to lines of sight of the wearer of the progressive power lens so as to assure improved optical performance with respect to the light beams equivalent to the wearer's lines of sight. In the international publication No. WO 2010/044260, the design is optimized, since the prescription and the conditions with which the lens is worn change from one wearer to another and thus the progressive power lens needs to be specially designed for each user.
In the art taught in the above publication, the contour of the lens surface of the progressive power lens is designed through optimization executed so as to improve the optical performance with respect to light beams reflecting the prescription, the conditions with which the particular wearer uses the lens and the like unique to the eyeglass wearer and thus assure optical performance closer to a target optical performance.